Cutter bit and holder therefor



sept. 15, 1942. F, L, FULKE 2,296,25

CUTTER BIT AND HOLDER THEREFOR Filed June 15, 1958 y ATTORNEYS.

Patented Sept. 1,5, 1942 CUTTER Brr AND HOLDER 'rHEREFoR Frank L. Filke, Terre Haute, Ind., assigner to Frank Prox Company, Inc., Terre Haute, Ind.,

a corporation of Indiana Application June 13, 1938, Serial No. 213,423

12 Claims.

I The 'object of the present invention is to provide an improved cutter bit with bit holding rireans for supporting the same in a mining ma- 'chine chain block; It is an object of the invention to provide such lmeans of such character that it may be used in a chain bit block originally designed to accommodate a conventional mine bit; so that, as the conditions encountered may indicate, either my improved bit or a conventional mine bit may be used in the same bit block.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the forms illustrated in the accompanying drawing, attention being called ,to the fact, however, that the drawing is illustrative only, and that change may be made in the specific constructions illustrated and described, so long as the sco-pe of the appended claims is not violated.

Fig. 1 is a plan View of a conventional bit block having associated therewith one form of bit and holder constructed in accordance with the present invention, parts being broken away for clarity of illustration;

Fig. 2 is a transverse section taken substantially on the line 2-2 of Fig. 1 and looking in the `direction of the arrows;

Fig. 3 is an elevation of the organization of Fig. 1;

Fig. 4 is a diagrammatic illustration of the manner in which my improved bits of the type illustrated in Figs. 1 to 3 may be punched from bar stock of proper cross section;

Fig. 5 is a transverse section of the bar stock illustrated in Figs. 4, 6, 7, and 8;

Fig. 6 is a fragmentary diagrammatic view illustrating the manner in whichanother form of bit included in my invention may be produced;

Fig. 7 is a fragmentary diagrammatic view illustrating the manner in which still another form of my improved bit may be produced; and

Fig. 8 is a fragmentary diagrammatic view illustrating the manner in which a fourth form of bit may be produced.

Referring more particularly to the drawing, and specifically to Figs. 1 to 5 thereof, it will be seen that I have illustrated 'a conventional mining machine bit block indicated generally by the reference numeral III and formed to provide a head II. A socket I2 is formed in said block, extending entirely through the same from the outermost surface of the head II. This socket I2 is the conventional mining machine chain bit block socket of the type illustrated, for

instance, in Fig. 6 of my co-pending application Serial No. 678,555, filed July 1, 1933.

Received in said socket I2 is a bit holder or clamping means indicated generally by the vreference numeral I3. As is clearly shown in'Fig. 2, said bit holder I3 comprises two elements, in-

dicated generally by the reference numerals I 4 and I5 in Fig. 2, cooperating to form a shank and a head, the shank being receivable in the socket I2 and the head being formed to provid-e a bit holding recess. In the particular form of the invention illustrated herein, the shank of the bit holder I3 is formed by the cooperation of Shanks I6 and I 8 formed, respectively, upon the elements I4 and I5; and the head is formed by the cooperation of head portions II and I9 of said elements I4 and I5. If desired, one of the Shanks, for instance, I6 may be formed with a swivel 20 received in a hole 2| in the other shank, for instance, I8. In theillustrated embodiment of the invention, the bit-receiving recess is formed partially as `at 22 in the element I4 and partially as at 23 in the element I5. It is 'to be noted that the 'mouth vof the bit-receiving recess is formed by outwardlybeveled surfaces 24 and 25 upon the respective elements I4 and I5, and that said elements retreat sharply .from the outer edges of said beveled portions, for a reason later V to be explained'. .30

In Figs. 1 to 3 inclusive, I have illustrated one particular form of bit received in the holder I3, said bit being indicated generally by the reference numeral 26. Obviously, the bit-'receiving recess formed by the cooperation of the recesses 22 and 23 will conform in contour to the shape of that portion of the bit which is received therein.

Preferably, the shank elements I6 and I8 will .be slightly reduced, as at 21, adjacent the point 'of engagement thereof by the conventional set 'screw28, in order to reduce the possibility of loss in case of loosening of said set screw.`

The bit 26 comprises a body portion 29 formed vto provide cutting points 3U and 3| joined by astraight edge 32; and cutting points 33 and 34 joined by a straight edge 35. The cutting points and 33 and the cutting points 3| 'and 34 are joined by edges of identical contour; and, in the `embodiment of Figs. 1 to 3, that contour comprises a sharply reentrant angle 36 merging, through a part circular surface 31, with a sharply reentrant angle 38.

As is clearly to be seen from a consideration of Fig. 2, the projecting portion of the bit and the portion of the bit received within the recess of the holder I3 are identical thin wedges, in transverse section; but adjacent the portion of the bit body midway between the edges 32 and 35, there are formed identical, laterally projecting ribs 39 and 40. The ribs 33 and 4I) closely overlie, respectively, the beveled surfaces 25 and 24 of the elements I5 and I4; thereby protecting the holder I3 very materially against abrasion during operation of the mining machine.

In order to guard against breakage of my holding means I3, I form in the block head II a transverse socket, intersecting the socket I2 substantially midway between its leading and trailing ends. In effect, this transverse socket comprises two grooves G'I and 68 in which are received depending shoulders 69 and 'It on the elements I4 and I5, respectively.

A bit of the type illustrated in Figs. 1, 2, and 3 may be inexpensively produced by punching from bar stock, such as that illustrated at 4I in Fig. 4,

-the punching being performed on the dotted lines of said figure. It will be readily apparent, from a consideration of that ngure, that very little stock lis wasted in this operation, and that the bits may be rapidly and inexpensively produced.

In Fig. 6 I have illustrated a bar 42, identical with the bar 4I, and from which may be punched bits of slightly different contour by punching on the dotted lines of Fig. 6, Such bits will be formed with cutting points 43, 44, 45, and 46 deining a rectangle, just as do the cutting points 30, 3l, 33, and 34 of Fig. 1. The points 43 and 44 will be joined by a straight edge 4'I, While the points 45 and 43 will be joined by a straight edge 43. The points 43 and 45 and the points 44 and 45 will be joined by edges of identical contour, each of said edges comprising a sharply reentrant angle 49, angularly merging with a straight edge 5I] which, in turn, angularly merges with a second sharply reentrant angle 5I. It will be seen that the bit of Fig. 6 is closely similar in contour to the bit of Fig. 4.

According to Fig. 7, a slightly greater change from the contour of the bit of Fig` 4 is noted. Thebar 52 is punched along the dotted lines illustrated in Figf'l to form bits each of which comprises four cutting points 53, 54:, 55, and 56 defining a rectangle. The points 53 and 54 are joined by a straight line 51 and the points 55 and 56 are joined by a straight line 58. The points 53 and 55 and the points 54 and 55 are joined by identical smooth concave curved edges59.

In Fig. 8 I have illustrated a manner in which.

still a further form of bit may be formed from bar stock 60 of the cross section illustrated in Fig. 5. By punching or sawing on the dotted lines of Fig. 8, bits of rhomboidal longitudinal. section may be formed. Each of those bits willv be formed with two cutting points 6I and 62 forming the termini of straight edges and 66, respectively. The opposite termini of said straight edges will be joined, respectively, with die cost, waste of metal, thick flash produced, and the like. When the sawing method is used, the bit shape is strictly limited to one which may be secured by sawing a straight line across the selected bar stock; and the cost of such cutting, whether with hack saws or with abrasive wheels, is excessive.

By the punching method of the present application, on the other hand, a bit having four cutting points, and having great strength, may be produced at low cost with exceedingly little waste of metal,

My selection of bar stock from which my bits are produced, I consider to be an important fea.- ture of the present invention. The bits produced from such stock are much thinner than bits heretofore used, so far as I am advised; thereby permitting deep penetration of a coal seam with the formation of relatively little dust. The ribs 39 and 4D eventually contact the coal and break it loose after the preliminary cut has been made, thus securing relatively coarse cuttings. In addition, the ribs stiffen and strengthen the bit and perform the important function of protecting the relatively soft holder elements against abrasion and again breakage which might occur if the holder elements should contact hard cores.

As will be apparent from a consideration of the drawing, in each of the bit forms disclosed, the length of surface extending from each edge of the bit to the adjacent parallel root of the lateral rib is at least twice the length of the surface extending from said root to the apex of said rib; and is at least twice the greatest thickness of the bit, viz., the distance between the apex of one rib and the apex of the opposite rib.

I claim as my invention:

1. In combination, a mining machine chain bit symmetrical with respect to a median line and formed to provide a plurality of selectively usable cutting points, clamping means for holding said bit with one of its points directed in the line of travel of the chain, and at least one rib formed on said bit and projecting therefrom in a direction generally transverse to the line of chain travel, said rib being wholly disposed outside said clamping means and closely overlying the latter.

2. The combination with a mining machine chain bit block, of bit-holding means carried by said block and projecting beyond the outermost surface thereof, and a hardened, plural pointed bit carried by said bit-holding means and projecting beyond the outermost surface thereof, the major part of the projecting portion of said bit being thinly wedge-shaped in cross section and a minor part of said projecting portion being formed to provide sharply projecting lateral ribs disposed immediately beyond the outermost portion of said bit-holding means and overlying the latter to protect the same against abrasion.

3. In combination with a mining machine chain bit block, bit clamping means carried by said block and projecting beyond the outer surface thereof, a hardened bit carried by said clamping means and projecting beyond the outermost surface thereof, the projecting portion of said bit being thinly wedge shaped in cross section from its outer end to a point adjacent the outermost portion of said clamping means, and being bluntly wedge shaped in cross section immediately adjacent said clamping means, the bluntly wedge shaped portion of said bit closely overlying the outermost surface of said clamping means to protect the same againstabrasion and to deliver wedging blows to coal adjacent the kerf cut by said thinly wedge shaped portion.

4. A mining machine chain bit comprising a' piece of hardened metal symmetrical with respect to a median line, each of the portions of said bit on opposite sides of such median line defining a cutting face which is long and thinly wedge shaped and flaring from its extremity to the region of said median line and short and bluntly Wedge shaped therefrom to said median line.

5. In combination with a mining machine chain bit block, bit clamping means carried by said block and projecting beyond the outer surface thereof, a hardened bit symmetrical with respect to a median line and carried by said clamping means and projecting beyond the outermost surface thereof, the projecting portion of said bit being thinly wedge shaped in cross section from its outer end to a point adjacent the outermost portion of said clamping means, and being bluntly wedge shaped in cross section immediately adjacent said clamping means, said clamping means embracing and enclosing all of one thinly wedge shaped portion of said bit and both bluntly wedge shaped portions of said bit being positioned outside said clamping means and closely overlying the outermost surface of said clamping means to protect the same against abrasion and to deliver wedging blows to coal adjacent the kerf cut by said thinly Wedge shaped portion.

6. In a mining machine cutter chain including a socketed bit block, the combination with a cutter bit comprising an element having four cutting points lying Substantially in the corners of an elongated rectangle having a major median line and a minor median line, said bit being symmetrical with respect to both of said median lines, and each of the portions of said bit lying on opposite sides of said'minor median line being formed to provide two oppositely facing cutting points, of a holder for said bit comprising a shank receivable in the socket of said block and a head disposed outside said block socket and embracing and enclosing all of one only of said portions.

'7. The combination with a mining machine chain including a bit block formed with a socket, of a cutter bit comprising a small piece of steel formed to provide two pairs of oppositely presented cutting points, said bit being symmetrical with respect to a line midway between said pairs of points, and the distance between the points of each pair being less than the distance CII between corresponding points of the respective pairs, and a holder comprising a shank receivable in said block socket and a head disposed outside said socket and formed to receive all of that portion of said bit lying on either side of said line to support said bit against shocks applied in any direction.

8. In a mining chain, a bit block having a socket adapted to receive therein a bit holder shank, said socket being enlarged in its lateral dimensions near its upper end by a transverse slot of lesser dimension in a front to rear direction than that of the lower portion of said socket, and said holder being provided with a shoulder snugly received in said slot.

9. In a mining chain link a socket, a bit holder having a shank adapted to be received in the socket and a head adapted to support a bit, and

lateral extensions on said head of lesser front to rear dimension than that of the shank, said extensions occupying a transverse slot adjacent the upper end of the socket.

l0. In a mining chain a bit block having a socket adapted to receive therein a bit holder shank, means laterally extending from the holder cooperating with a transverse opening at the mouth of said socket for gaining strength, and said means and said transverse opening both being of lesser dimension than the front to rear dimension of the socket.

11. In a mining chain a link formed with a socket of rectangular section adapted to receive a conventional mine bit, a bit holder having a shank extending into said socket and bit clamping portions extended outwardly therefrom, a four pointed bit clamped between elements of said bit holder with the major part of said bit located outwardly beyond said link, and at least one half of said bit body being located outwardly beyond said bit holder, said bit having its major axis outwardly and rearwardly inclined, and a screw engaging said holder shank.

12. A mining machine bit formed, on either side of a median plane, with a cutting face presenting a long thinly Wedge shaped section ilaring from its outer end to a point adjacent said median plane and a short bluntly Wedge shaped section merging, in said median plane, with the corresponding bluntly wedge shaped section on the other side of said median plane, the angles between the aring boundaries of said thinly wedge shaped portions being bisected by a common line perpendicular to said median plane.

FRANK L. FULKE. 

